1. The qualification and disqualification of patients and events in long term cardiovascular clinical trials;Gent,1979
2. Allocation of patients to treatment in clinical trials;Pocock;Biometrics,1979
3. Explanatory and pragmatic attitudes in therapeutic trials;Schwartz;J Chronic Dis,1967
4. A new design for randomized clinical trials;Zelen;N Engl J Med,1979